One vertex per element, one color per generator, with an edge from x to x·s.
(3,7)(6,8)(9,10,13,14)(11,12,15,16)(19,20)(23,24)(25,26)(27,32)(28,33)(29,37)(30,31)(34,39)(35,36)(38,40)(1,2,5,4)(3,6,7,8)(9,11,13,15)(10,12,14,16)(18,22)(23,24)(26,31)(27,33)(34,37)(35,40)(9,12)(10,11)(13,16)(14,15)(17,18)(19,23)(20,24)(21,22)(25,27,30,33)(26,32,31,28)(29,35,39,40)(34,38,37,36)(1,3)(2,6)(4,8)(5,7)(9,11)(10,12)(13,15)(14,16)(17,19,21,20)(18,23,22,24)(25,28,30,32)(26,33,31,27)(29,38,39,36)(34,35,37,40)(1,4,5,2)(3,8,7,6)(9,10)(11,12)(13,14)(15,16)(17,20,21,19)(18,24,22,23)(25,29,30,39)(26,34,31,37)(27,35,33,40)(28,36,32,38)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.